Some MS Patients Resist Physical Activity Boost

by John Gever John Gever Deputy Managing Editor, MedPage Today
June 02, 2014

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Action Points

Note that these studies were published as abstracts and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

DALLAS -- Multiple sclerosis (MS) patients who would benefit the most from an increase in physical activity were, unfortunately, those for whom an intervention designed to boost it was least effective, a researcher said here.

In a secondary analysis of data from an earlier, overall successful trial of an Internet-based exercise intervention, factors associated with the strongest responses included mild versus moderate disability, body weight in the normal range versus obesity, and relapsing-remitting versus progressive MS, according to Robert Motl, PhD, of the University of Illinois in Urbana-Champaign.

Separately, another analysis of the same trial data indicated that, in the overall study sample, the improvements seen in measures of physical activity were accompanied by reductions in time spent sitting.

Rachel Klaren, a graduate student in Motl's laboratory, reported that mean sitting time among all study participants (including dropouts) was lower by 1.6 hours per day compared with a wait-listed control group; and among those completing the study per protocol, the difference was 2.1 hours per day.

Motl and colleagues had developed a 6-month intervention geared to increasing physical activity in MS patients. It included a website providing information on how MS patients can become more physically active using social cognitive therapy techniques, as well as one-on-one live video coaching conducted over the Internet. Participants wore pedometers and had goals for the number of steps, recording their actual step counts in a diary.

At the 2014 meeting, Motl explained that physical activity is known to be beneficial in preserving mobility for MS patients, which typically diminishes over time even in those who remain in the relapsing-remitting phase.

The trial randomized 82 patients either to the intervention or to a wait-listed control. While on the wait-list, participants received no encouragement or coaching; they then entered the program at the trial's conclusion.

Who Responds, Who Doesn't

Overall, mean step counts increased from baseline by nearly 40% in the intervention group. But Motl said that the investigators noted that not every participant showed such an increase. In fact, some had marked decreases.

Relative to the wait-listed controls, only those in the intervention group with mild disability on the basis of Expanded Disability Status Scale scores showed increases in step counts, whereas the intervention had no effect for those classified with moderate disability (P<0.01 for the effect of disability status).

Similarly, the intervention was effective only in those with relapsing-remitting disease, not in those with progressive forms of MS (P<0.01 for the effect of clinical course) -- and it was effective only for those with body mass index values of 25 kg/m2 or less, not for those with higher values (P<0.05 for the effect of obesity status).

As it happens, the subgroups not benefiting from the intervention were those at the greatest risk for continued or accelerated disability progression, and therefore those for whom an increase in physical activity would have the greatest health benefit. Motl concluded that his, or other interventions, may need to be tailored more specifically to these patients to increase the chances of success.

Other factors, including whether patients were taking disease-modifying drugs or medications for specific MS symptoms, did not affect the intervention's impact, Motl indicated.

Effect on Sedentarism

Klaren noted that time spent sitting "has been described as 'the new smoking'" because of its adverse effects on a host of health outcomes.

Although the increase in step counts seen in the trial's primary results might logically entail a commensurate decrease in sitting times, it can't be assumed. Consequently, Klaren analyzed data on sitting time specifically collected in the trial.

As part of the baseline and 6-month follow-up evaluations, participants were asked to estimate their average daily time spent sitting down over the past 7 days. The analysis covered 70 participants who had provided baseline data (intent-to-treat sample), of whom 13 did not complete the intervention.

In the overall group and after adjusting for baseline differences, the mean daily sitting time in the intervention group at follow-up was 7.2 hours (SE 3.3), compared with 8.8 (SE 3.3, P<0.05) for the wait-listed controls.

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